The accounting principle of accrual means that you should register something when the fact that origins the right for the future payment/collecting occurs. It does not matter if the payment is done later, the fact that made you to pay was already done, so we apply accrual and say we already owe that money that we pay later.
In this example, Sally used the principle of accrual for the things in June that she later paid in July... but her expenses were origined in June, so they apply to June.
